ory, mike. 've been telling you if the u.s. passes the tuesday night deadline without a deal to increase the debt ceiling, then the government is going to have to make some very tough choices as to what gets paid and what doesn't. that's causing anxiety from wall street to the battlefields of afghanistan. as the chairman of the joint chiefs of staff, admiral mike mullen, discovered for himself today, nbc's jim miklaszewski is traveling with him. >> reporter: here at the hot spots of kandahar, american soldiers and marines are still dodging bullets, rockets and road side bombs every day. amazingly, when they had a cc1: chance to throw questions at the chairman of the joint chiefs of staff, admiral mike mullen, their number one concern was the ongoing debate back home over the debt ceiling. >> the checkbook is not unlimited. >> reporter: admiral mullen told soldiers at kandahar that if the talks failed they'd still have to fight but they might not get paid. >> there are plenty of you that are living paycheck to paycheck: so if paychecks were to stop, it can have a devastating impact, and it can have a devastating impact pretty quickly. >> reporter: at camp leatherneck, mullen told marines given the state of the u.s. economy, all the services face a cutback in the size of the force, and maybe even military benefits. >> we're going to have to tighten our belts.